A novel Electro-Fenton process characterized by aeration from inside a graphite felt electrode with enhanced electrogeneration of H2O2 and cycle of Fe3+/Fe2+

A novel Electro-Fenton process characterized by aeration from inside a graphite felt electrode with enhanced generation of H2O2 and cycle of Fe3+/Fe2+ was proposed. The new type of Electro-Fenton process was used to degrade organic pollutants via graphite felt electrode aeration (GF-EA). The H2O2 concentration by GF-EA could reach 152–169 mg/L in a wide pH range (3–10), which was much higher than that achieved by graphite felt using solution aeration (GF-SA, 37–113 mg/L). For the degradation of nitrobenzene (NB), benzoic acid (BA), bisphenol A (BPA), and sulfamethoxazole (SMX) at pH 5.5, the percentage degradation by GF-EA could reach 55%, 56%, 80%, and 60% higher than those obtained by GF-SA, respectively. The solution TOC removal by GF-EA were enhanced by 29–51% relative to GF-SA. Mechanism analysis showed both OH and ferryl species were involved in the reaction system, and the amounts of OH and dissolved iron species in GF-EA group were 7.7 times and 4–8 times higher than those in GF-SA group, respectively. Besides, the mass transfer rate of GF-EA system was 5.4 times higher than that of GF-SA system. High amounts of H2O2, dissolved iron species and OH were attributed to the enhanced mass transfer of O2 and the solution.